The recent advent of computer-controlled machinery has created a need for highly skilled technicians who can diagnose malfunctions of both the electro-mechanical parts of the machinery and also the computer which controls it. Today, repair technicians must be skilled in mechanics, electric machines and electricity as before, and now also skilled in digital electronics. There is a shortage of such highly-skilled technicians.
Even a skilled technician may take a long time to diagnose a problem if he or she is not familiar with the particular piece of equipment needing repair. In a manufacturing plant where various machines need attention, it may be difficult for the repair personnel to know them all well enough to perform efficient trouble-shooting.
If repair technicians are not highly skilled for repairing a particular machine, then programmed repair guides may be provided to direct them through all the required tests needed to diagnose or repair that machine. These guides might take the form of outlines, printed instruction sets, flowcharts, and the like. The instruction set may be printed on paper, recorded on magnetic tape, or recorded in some other way.
The simplest kind of instruction set is that for a simple sequence of tests, one step at a time, to a technician. For more sophisticated machinery a flowchart-type instruction set may be best. With a flowchart the test sequence branches depending on the test result.
A flowchart instruction set may be physically presented in the same ways as a simple sequence, but if the flowchart is complex, then a computer, microprocessor, or CPU (central processing unit) with digital memory may be the best choice for holding the instruction set. The instructions are electronically loaded into the memory; physical interfaces and programs are provided for the technician to interact with the CPU to negotiate the flowchart.
The interface between the instruction set flowchart and the technician has two directions of information flow. First, the instructions stored in the memory must be verbalized, either visually or audibly, and presented to the technician. The program may also include non-verbal instruction aids, such as maps or diagrams which can be viewed on the computer screen. Second, the technician must be able to step through the program by sending digital messages to the CPU. A standard personal computer with video monitor can be used for holding the instruction set. The instructions stored in memory can be written on the screen, and the keyboard used to prompt the CPU to step or branch through the flowchart program.
The instruction set might pose questions, ask for specific data, or give directions, to enable the flowchart branches to be negotiated: for example, "If the voltage is higher than 25 volts, go to step 7", "Is the voltage above 25?", or "enter the voltage."
How the flowchart instruction set is written depends upon the number of inputs to the computer. For example, if only "yes" and "no" buttons are provided for the technician to communicate to the computer, a flowchart branch point might contain the instruction, "Is the voltage higher than 25 volts?" If a number keypad is provided for the technician, then the instruction at the same point might be, "Enter the voltage on the keypad."
With computerized or digital guides, the technician need not keep track of where in the flowchart the testing is; the CPU only provides the current instruction, and no others.
While a standard personal computer is expensive, fragile, bulky and immobile, a smaller computerized guide can be less bulky than books and charts.
In the case of a computer-controlled machine, malfunctions could be caused by the electrical and mechanical parts of the machine, or by the control computer, or by some interaction between the control computer and the electro-mechanical parts. The prior art has not addressed the problem of troubleshooting computer-controlled machinery. It has utilized various repair strategies and equipment, but has not shown any combination of these strategies and equipment which optimizes their repair.
Most industrial machines are electro-mechanical. They have mechanical parts which are powered or controlled by electricity. A sewing machine, for instance, usually has an electric motor, and may include sensors, step motors, solenoids, etc.
Testing an electro-mechanical machine usually requires a voltmeter to measure the electric tension at various points in the machine. Testing may also require a voltage or current generator, which provides, rather than detects, an electric signal. The generated voltage can be applied to various points in the machine to drive particular devices or sub-parts. A generator may produce pulses of electricity as well as steady direct current.
A technician usually will use a "probe" to apply or sample voltages at points of a machine or circuit. Such a probe usually consists of a metal spike which is mounted on an insulating handle and is electrically connected to a meter or generator by a flexible wire.
Where the machine under test includes a control computer, the machine will typically include circuits for "translating" between the electricity of the devices and the digital signals of the computer. These circuits are called "A/D" (Analog to Digital) converters and "D/A" (Digital to Analog) converters. For example, a velocity sensor might give out a steady voltage whose amplitude corresponds to speed. If the computer is to "know" what the speed is, the steady voltage must be translated into binary code by the A/D converter. Binary code is a sequence of "ones", or voltage pulses, and "zeroes" represented by the absence of a pulse. Conversely, if the computer directs a motor to run, a digital signal from the computer cannot be applied directly to the motor; it must be applied to a D/A converter, whose output may be applied to the motor or to a relay connected to the motor.
Digital signals are usually sent over a "data bus". Analog electricity is usually conducted by ordinary wires or cables.
Voice synthesis has recently been used when technicians are to be notified of conditions or given instructions. A voice is very effective for alarms, because it will simultaneously alert and inform a person, without regard for what direction the person gazes and without requiring that the person look anywhere. It also frees a worker free from having to look at printed instructions while working.
The prior art shows various applications of voice synthesis. A simple application of alarm-type voice notification is shown by Shibazaki et al. in U.S. Pat. No. 4,459,673. Their photocopier uses an artificial voice to tell the operator that the machine is out of paper or jammed. The voice merely serves as a display.
Jerome Lemelson and Christian Grund disclose in U.S. Pat. No. 4,563,770 an electrical multi-meter (combined volt, ohm and amp meter) which not only displays the electrical reading on a meter face, but also speaks the reading. The user need not look at the visual display while working on an electrical circuit. A voice synthesizer is used to generate the speech. In this invention also, the voice merely serves as a display.
U.S. Pat. No. 4,829,579 of Ryuzo Harada et al. shows a voice synthesizer attached to a chain saw. The artificial voice steps the user through a series of questions, such as, "Is there the fuel?" and "Is there the lubricating oil?" The user must push a yes button in response to each question before the saw will operate. A similar application is taught by Inoue et al. in U.S. Pat. No. 4,420,813 which vocalizes an automobile checklist. These are not trouble-shooting or diagnostic inventions, but rather normal operation checklists.
An electronic sewing machine with synthetic voice is described in U.S. Pat. No. 4,465,003 of Makabe et al. The voice describes the state of the machine.
Leonard, in U.S. Pat. No. 4,872,195, teaches the use of a voice synthesizer for a remote alarm unit. A user can telephone to the unit and receive a synthetic-voice report on the status of a transmitter at the remote location.
Walter Vogelsberg discloses electronic circuitry for generating a voice in his U.S. Pat. No. 4,519,027.
U.S. Pat. No. 4,821,217, issued to Brian Jackson and D. Wilson, describes an automatic test station, including a voice generator, for group testing of jet engines.
The Jackson test station includes a data acquisition computer. This computer serves basically as a switchboard and memory for the testing, allowing many jet engines to be tested in a group and saving time. It does not instruct the jet technician to perform tests according to a flowchart; it does, however, ask for instructions from the technician.
It will be appreciated that the prior art does not disclose any test unit which is adapted to trouble-shooting equipment which has both electro-mechanical parts and a control computer. Indeed, there is disclosed no prior invention which is even physically adapted for connection to a computer via a data bus, as well as for electrical connection to relays, switches, and the like.